A Look Inside & Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand the internal components of a PSU much better. Our main tool for the disassembly of the PSU is a Thermaltronics TMT-9000S soldering and rework station. It is of extreme quality and is equipped with a matching de-soldering gun. With such equipment in hand, breaking apart every PSU is like a walk in the park!


The OEM of this unit is HEC/Compucase, and the 500B actually shares the platform with the be quiet! L8-500 unit we reviewed a while ago. HEC/Compucase is a popular choice for this price category because its units are affordable and perform decently. The secondary side uses a group-regulation scheme, which will give the PSU a hard time with our Haswell compliance test. Also, the components rectifying all of its rails are passive, which will reduce efficiency.


A small PCB located behind the AC receptacle houses the first part of the transient filter. There, we found one X and two Y caps along with a CM choke. The second part of the same filter is installed on the main PCB and consists of one CM choke, two Y caps, a single X cap, and an MOV (Metal Oxide Varistor), with the latter offering protection against surges coming from the mains network.


The single bridge rectifier is bolted onto a dedicated heatsink.


In the APFC, two MDF18N50 fets and a BYC8-600 boost diode are used, and the hold-up cap is provided by CapXon (400 V, 270 μF, 85°C). We expected a higher quality cap here, not one from CapXon.


Similar to the be quiet! L8-500, the main switchers are two MDF18N50 fets. The combo PFC/PWM controller is a Champion CM6800TX IC.


The standby PWM controller is a TNY279PN IC by Power Integrations.


The +12V rail is generated by two STPS30L45CT SBRs. The 5V rail is rectified by two 40U60CT SBRs and 3.3V is rectified by a pair of STPS30L45CTs. The only difference to the BQ L8-500 here are the SBRs that regulate the +12V rail, with the be quiet! unit's pair of PFR30L45CTs being more efficient than the STPS30L45CTs, so we expect the EVGA 500B to be less efficient than be quiet!'s offering.


All caps in the secondary side are provided by Teapo and are rated at 105°C. We really would not want to see lower quality caps here (e.g. CapXons).


There are only two toroidal chokes, which goes to show that a group regulation scheme is used in the secondary side, where the the 12V and 5V rails utilize the large choke, while the smaller choke filters and rectifies the 3.3V rail.


The protections IC, a Weltrend WT7527 IC, supports OCP for up to two +12V rails. It is soldered to the component side of the main PCB.


Soldering quality is good for this price category.


The fan has HEC's logo in the middle, and its model number is EFS-12E12H (12 V, 0.25 A). It is not the quietest, but the controller keeps rotational speeds at low speeds under normal conditions. The letter "S" in EFS probably stands for "sleeve bearing".